StepFun (阶跃星辰) is a Shanghai-based AI foundation-model company whose open platform serves the Step model family — multimodal reasoning (step-3.7-flash), fast language reasoning (step-3.5-flash), vision, image generation and editing (step-2x-large, step-image-edit-2), and a deep audio stack spanning TTS, voice cloning, ASR, and end-to-end realtime… - View it on GitHub